Late years, an electric control-based operation system has been increasingly used in various products. In such a system, a wire harness has a key role in connecting a controller to various electric components, and defects in a wire harness have a direct impact on total quality of a product.
Thus, in a wire harness production process, it is required to inspect a production quality of a wire harness. Specifically, a wire harness has heretofore been inspected in such a manner that a connector housing attached with a plurality of terminals of a wire harness (or an assembly of terminal-fitted wires) is mounted on an inspection jig, and then an inspection probe is brought into mechanical contact with each of the terminals to perform continuity check.
For example, Japanese Patent Laid-Open Publication No. 08-146070 discloses an inspection apparatus, wherein, in an inspection mode, an output-side inspection connector for receiving an inspection signal is mechanically connected to an output-side connector (or connector housing) fitted with one end of a terminal-fitted wire assembly having the other end inserted in an input-side connector pre-connected to an input-side inspection connector for supplying the inspection signal, and then the inspection signal is applied from the input-side inspection connector to each terminal of the terminal-fitted wire assembly inserted in the input-side connector so as to inspect a production quality of the wire harness (unit of the input-side and output-side connectors and the terminal-fitted wire assembly).
However, the continuity check based on mechanical contact using the inspection probe involves a problem about occurrence of plastic deformation in the terminal due to defects in the inspection probe.
In recent trend, the size of a terminal has become smaller and smaller along with downsizing of connectors, it becomes difficult to ensure an end-surface area of a terminal, which is required for adequate contact with an inspection probe. Thus, some inspections have to be performed by bringing an inspection probe into contact with a tongue portion of a terminal to ensure a sufficient contact surface. In this case, even slight change in contact force of the inspection probe is likely to cause plastic deformation in the terminal tongue.
Moreover, if a positive result is obtained in the continuity check, the wire harness will be determined to be normal regardless of occurrence of the plastic deformation, and this defect will undesirably come up to the surface after the wire harness is incorporated in a product. Thus, there is a strong need for providing a wire harness checker capable of inspecting a wire harness without contact between a terminal and an inspection probe.
Further, an inspection operation about faulty-wiring has heretofore been performed after completion of an operation for inserting a plurality of terminals of a terminal-fitted wire assembly into a connector. Thus, if a faulty-wiring is detected, it is necessary to perform a significantly time-consuming operation for detaching and re-inserting the terminal of the relevant terminal-fitted wire.